Retinal function with lens-induced myopia compared with form-deprivation myopia in chicks

BACKGROUND

The retina is known to be involved in the development of form-deprivation myopia (FDM); however, it is not clear whether the retinal changes that lead to lens-induced myopia (LIM) are the same as those involved in FDM. To gain insight into the retinal mechanism(s) that cause myopia, we investigated differences in the results of electroretinography (ERG) in eyes with FDM and LIM.

METHODS

LIM or FDM was induced in chick eyes by placing various powers of spectacles or an occluder over the left eyes of 6-day-old chicks. After 6 days, the spectacles or occluder was removed, refraction and axial length were measured and ERG was performed. Results for eyes treated with spectacles and those treated with occluders were compared.

RESULTS

Refraction and axial length changed concomitant with the power of the lens used, but components of the ERG of eyes with LIM were not related to the power of lens added. Refraction and axial lengths of eyes covered with a -16 D lens did not differ from these values in eyes covered with an occluder. The a- and b-waves were also similar for the two groups. However, oscillatory potentials decreased significantly in the chicks with FDM.

CONCLUSIONS

Retinal function differs in LIM and FDM, as indicated by differences in the oscillatory potentials. This difference may stem from the fact that in FDM the retinal image is continuously defocused, whereas images are ultimately focused on the retina in LIM.

Selective survival of a thermostable direct hemolysin-producing Vibrio parahaemolyticus in the alimentary tract of a juvenile estuarine gastropod (Clithon retropictus)

Juvenile estuarine gastropods (Clithon retropictus), maintained in ultraviolet ray-irradiated recirculating artificial seawater with a salinity of 20/1000 at 28 degrees C, preserved thermostable direct hemolysin (TDH)-producing strain D-3 of Vibrio parahaemolyticus at a level of 10(4)-10(5) colony forming units per gram (cfu/g) and TDH-non-producing strains N-18 and R-13 at a level of 10(1)-10(2) cfu/g in the alimentary tract for at least 21 days after ingestion. In adults, the numbers of the three strains decreased to a level of 10(0) cfu/g within 21 days under the same conditions. This evidence supports our recent observations that TDH-producing strains increased to a high level in the summer months in the presence of high levels of TDH-non-producing strains in the alimentary tract of juvenile C. retropictus at estuaries in Japan.

[131I SPECT-imaging with body outline using convenient lightweight source]

In order to make the body outline clearly in SPECT images, we devised a simple line source holder with the objectives to have a lightweight line source, to reduce the radiation exposure to the staff and to make the system readily available. This technique was applied to evaluate the localizing lesions in patients with radioiodine treatment of thyroid cancer. 131I-SPECT imaging with body outline was found to be effective in 86.7 percent (13/15) of the cases compared with planar imaging. Clinically, the results significantly helped in the discrimination between cervical lymph node metastasis and thyroid bed, and between mediastinal lymph node metastasis and bone metastasis. In the case of multiple lung metastasis demonstrating diffuse accumulation in the lung fields, 131I-SPECT imaging with body outline did not provide an increase in sensitivity compared with planar imaging. This method is easy to perform and it is considered to be useful for localization of abnormal accumulation, relative to the body outline.

Electron resonance studies on the influence of anionic surfactants on human skin

BACKGROUND

When skin is exposed to chemicals, raw materials interact with the lipid structure of the stratum corneum. At least two types of disorders can be distinguished--that of alkyl chains inside one lipid bilayer and that of lipid layer arrangement. Electron spin resonance (ESR) spectroscopy of a nitroxide spin label is a valuable method in the study of biological membranes.

OBJECTIVE

These experiments define the effect of anionic surfactants on the lipid bilayer of human stratum corneum.

METHODS

5-Doxyl stearic acid (5-DSA) was used as the spin label. Sodium lauryl sulfate (SLS) and sodium lauroyl-L-glutamate (SLG) were the anionic surfactants studied. ESR spectrum measurements of surfactant-treated stratum corneum were performed and order parameters calculated.

RESULTS

1% of SLS leads to an obvious change in ESR spectra--from strongly to weakly immobilized spectra. The molecular motion of spin labels (5-DSA) in SLS-treated stratum corneum is different from that of spin labels in the untreated stratum corneum. The ESR spectra suggest that SLS affects the spin label binding to the lipid membrane and causes an increase in the mobility of bilayers. On the other hand, there were minimal changes in ESR spectra of 1% of SLG-treated stratum corneum. An increase in fluidity of skin lipid bilayers suggests a decrease in the skin barrier function.

CONCLUSION

ESR may provide a facile and robust method to define the subclinical irritancy potential of anionic surfactants and other materials.

Reducing sugars trigger oxidative modification and apoptosis in pancreatic beta-cells by provoking oxidative stress through the glycation reaction

Several reducing sugars brought about apoptosis in isolated rat pancreatic islet cells and in the pancreatic beta-cell-derived cell line HIT. This apoptosis was characterized biochemically by inter-nucleosomal DNA cleavage and morphologically by nuclear shrinkage, chromatin condensation and apoptotic body formation. N-Acetyl-L-cysteine, an antioxidant, and aminoguanidine, an inhibitor of the glycation reaction, inhibited this apoptosis. We also showed directly that proteins in beta-cells were actually glycated by using an antibody which can specifically recognize proteins glycated by fructose, but not by glucose. Furthermore, fluorescence-activated cell sorting analysis using dichlorofluorescein diacetate showed that reducing sugars increased intracellular peroxide levels prior to the induction of apoptosis. Levels of carbonyl, an index of oxidative modification, and of malondialdehyde, a lipid peroxidation product, were also increased. Taken together, these results suggest that reducing sugars trigger oxidative modification and apoptosis in pancreatic beta-cells by provoking oxidative stress mainly through the glycation reaction, which may explain the deterioration of beta-cells under conditions of diabetes.

[Way to the detection of Mars life]

In this review, I would like to introduce how we can detect the possible life on Mars. Even though the quantitative estimation of the possibility of biogenesis on Mars is difficult, Dr. McKay and his colleagues work has thrown a tiny light for this possibility. Considering Mars environmental conditions, the possible life is microorganisms. The detection of microorganisms in natural environments is not easy even on Earth due to the premature detection technique. We have developed a method based on the fluorescence microscopic technique. This method proved to be successful for the detection of terrestrial microorganisms. Even some pre-biotic cells can be detected. We are developing a miniature detection apparatus which meet the required standard for installing on the Mars landers. We also propose the ground based experiments using Martian meteorites or pseudo-Martian rocks.

The localized melting of mini-F origin by the combined action of the mini-F initiator protein (RepE) and HU and DnaA of Escherichia coli

Replication of mini-F plasmids requires the initiator protein RepE, which binds specifically to four iterons within the origin (ori2), as well as some host factors that are involved in chromosomal DNA replication. To understand the role of host factors and RepE in the early steps of mini-F DNA replication, we examined the effects of RepE and the Escherichia coli proteins DnaA and HU on the localized melting of ori2 DNA in a purified in vitro system. We found that the binding of RepE to an iteron causes a 50 degrees bend at or around the site of binding. RepE and HU exhibited synergistic effects on the localized melting within the ori2 region, as detected by sensitivity to the single-strand specific P1 endonuclease. This opening of duplex DNA occurred around the 13mer of ori2, whose sequence closely resembles the set of 13mers found in the chromosomal origin oriC. Further addition of DnaA to the reaction mixture increased the efficiency of melting and appeared to extend melting to the adjacent AT-rich region. Moreover, DNA melting with appreciably higher efficiencies was observed with mutant forms of RepE that were previously shown to be hyperactive both in DNA binding in vitro and in initiator activity in vivo. We propose that the binding of RepE to four iterons of ori2 causes bending at the sites of RepE binding and, with the assistance of HU, induces a localized melting in the 13mer region. The addition of DnaA extends melting to the AT-rich region, which could then serve as the entry site for the DnaB-DnaA complex, much as has been documented for oriC dependent replication.

[Usefulness of MRA in an infant with cerebral infarction due to streptococcal meningitis]

We described a 4-month-old boy with cerebral infarction due to streptococcal meningitis. He complained of cough and high fever for 2 days. On the next day he admitted to our hospital because of bad humor, drowsiness, and vomiting associated with high fever, respiratory failure and loss of consciousness. On admission, he had opisthotonic posturing, anisocoria and elevated deep tendon reflexes with left side dominance. The cerebrospinal fluid showed increased cells (564/mm3), protein (295 mg/dl), and decreased sugar (1 mg/dl). Streptococcus pneumoniae was detected in the cerebrospinal fluid. Despite intensive treatment by antibiotics, glycerol, and dexamethasone, general condition was worsened, MRI showed a high intense area along the territory of bilateral anterior cerebral arteries and left middle cerebral artery 3-D time-of-flight MRA revealed a decreased signal of these arteries, confirming cerebral infarction. Recanalization of the arteries were observed 17 days after the first MRA examination. Since complication of cerebral infarction influences the prognosis of meningitis, repetitive MRA is very beneficial in patients with bacterial meningitis in order to evaluate the vascular lesion.

Simultaneous observation of regional cerebral blood flow and event-related potential during performance of an auditory task

Reduced amplitude of the P300 component has been reported consistently in patients with neurological and psychiatric disorders. It is unclear, however, how such patients' cognitive dysfunction is related to their P300 abnormality. Further basic knowledge regarding neural substrates for P300 generation is required for gaining an understanding of the pathological significance of the P300 amplitude reduction. To determine the brain structures involved in P300 generation, we observed the event-related potential and the regional cerebral blood flow (rCBF) in 10 normal subjects performing an oddball discrimination of pure tones. The rCBF value was assessed quantitatively with the aid of single photon emission computed tomography using technetium-99m hexamethylpropylene amine oxime. During the task performance, significant activation was observed in the posterior superior temporal and inferior parietal regions of the right hemisphere. In addition, positive correlation of the task-related increase in rCBF with the simultaneously recorded P300 amplitude was observed in the right but not the left posterior superior temporal region. These findings indicate that activation of the right non-verbal auditory area might modulate P300 generation during pure-tone discrimination.

Accumulation of Tc-99m MIBI in breast lymphoma: comparison with Ga-67 citrate

We report 2 cases of malignant lymphoma of the breast which were clearly shown on total body imaging as well as on SPECT with Ga-67 and Tc-99m MIBI. Tumor accumulation of Ga-67 was seen in all cases including a recurrent tumor. Ga-67 scintigraphy is useful for follow up in detecting relapse, as well as in predicting responses to therapy. Tc-99m MIBI was found to accumulate in the malignant lymphoma of the breast, and especially SPECT images of breast lesions provided better contrast than planar images, and Tc-99m MIBI SPECT could diagnose localization of the tumor because there was no uptake by the breast. But the Tc-99m MIBI accumulation of the tumor was lower than Ga-67.

[Evaluation of 99mTc-MIBI to predict chemotherapeutic response in patients with small cell lung carcinoma]

The purpose of this study was to evaluate the relationship between 99mTc-MIBI (MIBI) accumulation and the response to chemotherapy. Twelve patients with small cell lung carcinoma (SCLC) underwent MIBI SPECT before chemotherapy. SPECT data were acquired 15 minutes and 2 hours after the injection of 600MBq MIBI. The early ratio (ER), delayed ratio (DR) and retention index (RI) was measured. Tumor response were classified into complete remission (CR), partial remission (PR) and no change (NC) by follow-up CT examination. The mean +/- standard deviation of ER was 3.10 +/- 0.85 (n = 4) for CR, 2.72 +/- 0.46 (n = 5) for PR and 2.43 +/- 0.95 (n = 3) for NC. DR was 3.05 +/- 1.11 for CR, 2.64 +/- 0.30 for PR and 1.90 +/- 0.82 for NC. RI was -3.0 +/- 11.69 for CR, -1.84 +/- 11.03 for PR and -18.19 +/- 38.51 for NC. CR, DR and RI were not significantly correlated with tumor response (CR, PR, NC) MIBI has the potential to predict the response to chemotherapy in SCLC.

Evaluation of the genotoxicity of stevioside and steviol using six in vitro and one in vivo mutagenicity assays

Stevioside, a constituent of Stevia rebaudiana, is commonly used as a non-caloric sugar substitute in Japan. The genetic toxicities of stevioside and its aglycone, steviol, were examined with seven mutagenicity tests using bacteria (reverse mutation assay, forward mutation assay, umu test and rec assay), cultured mammalian cells (chromosomal aberration test and gene mutation assay) and mice (micronucleus test). Stevioside was not mutagenic in any of the assays examined. The aglycone, steviol, however, produced dose-related positive responses in some mutagenicity tests, i.e. the forward mutation assay using Salmonella typhimurium TM677, the chromosomal aberration test using Chinese hamster lung fibroblast cell line (CHL) and the gene mutation assay using CHL. Metabolic activation systems containing 9000 g supernatant fraction (S9) of liver homogenates prepared from polychlorinated biphenyl or phenobarbital plus 5,6-benzoflavone-pretreated rats were required for mutagenesis and clastogenesis. Steviol was weakly positive in the umu test using S.typhimurium TA1535/pSK1002 either with or without the metabolic activation system. Steviol, even in the presence of the S9 activation system, was negative in other assays, i.e. the reverse mutation assays using S.typhimurium TA97, TA98, TA100, TA102, TA104, TA1535, TA1537 and Escherichia coli WP2 uvrA/pKM101 and the rec-assay using Bacillus subtilis. Steviol was negative in the mouse micronucleus test. The genotoxic risk of steviol to humans is discussed.

A role of peroxides in Ca2+ ionophore-induced apoptosis in cultured rat cortical neurons

The implication of reactive oxygen species for the Ca2+ ionophore ionomycin-induced apoptosis was investigated in cultured cortical neurons from embryonic rats. Ionomycin increased the production of intracellular peroxides as measured by flow cytometric analysis with 6-carboxy-2'7'-dichorodihydrofluorescein diacetate, di(acetoxymethyl ester). Low doses of ionomycin increased the level of manganese-superoxide dismutase (Mn-SOD). In addition, N-acetyl-L-cysteine prevented apoptotic neuronal death induced by ionomycin in a dose-dependent manner. Buthionine sulfoximine suppressed the effect of N-acetyl-L-cysteine. These results suggest that peroxides and redox-regulation play an important role in the apoptosis of neurons induced by elevation of intracellular Ca2+ concentration.

Differences in the influence of AIN-purified and non-purified diets on the development of hypertension in SHR and DOCA-salt hypertensive rats

The influence of non-purified and AIN purified diets on the development of hypertension was examined in deoxycorticosterone acetate (DOCA)-salt hypertensive rats and SHRs. For DOCA-salt hypertensive rats, the development of hypertension was slower in rats fed the AIN 76-purified diet than in those fed the non-purified diet throughout the experimental period of about five weeks. In an experiment using spontaneously hypertensive rats (SHRs), 4-week-old rats were fed either a non-purified diet, a AIN76-purified diet or a AIN93G-purified diet for about nine weeks. In the first 1-2 weeks, the blood pressure was lower in the SHRs fed the AIN93G-purified diet than in those fed the non-purified diet. However, no significant difference in blood pressure was observed within the SHR group thereafter.

Lactoferrin-mediated protection of the host from murine cytomegalovirus infection by a T-cell-dependent augmentation of natural killer cell activity

The administration of bovine lactoferrin (LF) with 1 mg/g body weight before the murine cytomegalovirus (MCMV) infection completely protected the BALB/c mice from death due to the infection. In these LF-treated mice, a significant increase in the activity was found in the NK cells but not in the cytolytic T lymphocytes which recognized an MCMV-derived peptide. Moreover, the elimination of the NK cell activity by an injection with anti-asialo GM1 antibody abrogated such augmented resistance, thus supporting the hypothesis that the LF-mediated antiviral effect in vivo is performed through the augmentation of NK cell activity. No such LF-mediated antiviral effect in vivo with the increased NK cell activity was found in athymic nude mice, whereas it was restored completely by the transfer of splenic T cells from LF-treated donors. These findings therefore suggest that T lymphocytes induce both the augmentation of NK cell activity and the resultant antiviral effect in the LF-treated hosts.

Three-dimensional labeling program for elucidation of the geometric properties of biological particles in three-dimensional space

For all biological particles such as cells or cellular organelles, there are three-dimensional coordinates representing the centroid or center of gravity. These coordinates and other numerical parameters such as volume, fluorescence intensity, surface area, and shape are referred to in this paper as geometric properties, which may provide critical information for the clarification of in situ mechanisms of molecular and cellular functions in living organisms. We have established a method for the elucidation of these properties, designated the three-dimensional labeling program (3DLP). Algorithms of 3DLP are so simple that this method can be carried out through the use of software combinations in image analysis on a personal computer. To evaluate 3DLP, it was applied to a 32-cell-stage sea urchin embryo, double stained with FITC for cellular protein of blastomeres and propidium iodide for nuclear DNA. A stack of optical serial section images was obtained by confocal laser scanning microscopy. The method was found effective for determining geometric properties and should prove applicable to the study of many different kinds of biological particles in three-dimensional space.

Selective growth of thermostable direct hemolysin-producing Vibrio parahaemolyticus in the alimentary tract of a gastropod, Clithon retropictus, at a selected estuary in Japan

Thermostable direct hemolysin (TDH)-producing Vibrio parahaemolyticus increased in cell number in the alimentary tract of a gastropod. Clithon retropictus, from an undetectable level in July to 2.0 x 10(3)/g in September 1991 at the Sada estuary in the southern part of Japan. It was not detected in microalgae, foods of the gastropod, at the estuary or muddy sediments at a neighboring fishing port. The strain was not detected at two estuaries and two fishing ports ecologically separated from the Sada estuary. Serotypes of the isolated strains were different from those registered as clinical isolates. Our results confirm that TDH-producing V. parahaemolyticus grows selectively in the gastropod at some estuaries in Japan.

Physical interactions among Mcm proteins and effects of Mcm dosage on DNA replication in Saccharomyces cerevisiae

Mcm2, Mcm3, and Mcm5/Cdc46 are conserved proteins essential for the initiation of DNA synthesis at replication origins in Saccharomyces cerevisiae. The accumulation of these proteins in the nucleus before the onset of DNA synthesis suggests that they play a role in restricting DNA synthesis to once per cell cycle. In this work, we show that Mcm2, Mcm3, and Mcm5 self-interact and interact with one another to form complexes. Mcm2 and Mcm3 are abundant proteins, present in approximately 4 X 10(4) and 2 X 10(5) copies per cell, respectively. Reducing the dosage of Mcm2 by half results in diminished usage of specific replication origins. These results together suggest that a significant molar excess of Mcm proteins relative to replication origins is required for the proper initiation of all replication origins.

Mini ecosystem in space--preliminary experiment on board STS-77

An enclosed ecosystem which is stable on Earth will behave differently when brought into space. Micro-gravity and radiation will affect the dynamics of material circulation or the activities of small creatures of the ecosystem. One series of space experiments aiming to address such issues was planned in the United States (It is termed as ABS--Autonomous Biological System) and Japanese group has been involved with cooperating with the analysis of the flight samples. Before the ecosystem will be on board Russian Space Station "Mir" later 1996 for 3 months, a preliminary flight was carried out in May 1996 on Space Shuttle (STS-77) for 10 days flight. It was the first of such experiments to fly one whole ecosystem in space.

Induction of apoptotic cell death by methylglyoxal and 3-deoxyglucosone in macrophage-derived cell lines

Production of 2-oxoaldehyde compounds increase during hyperglycemic conditions and is cytotoxic to susceptible cells. We have investigated the effects of methylglyoxal and 3-deoxyglucosone at physiological concentrations on monocytic leukemia U937 cells and other cell lines. Both ladder formation of DNA and nuclear fragmentation were observed in the cells treated with these agents, indicating that apoptotic cell death was induced. The fluorescent intensity of an oxidation sensitive dye (2',7'-dichlorofluorescin) was increased in U937 cells but not in other cells in which apoptosis was not induced. The levels of intracellular glutathione, however, were only slightly changed. Apoptosis and intracellular oxidant levels were enhanced by buthionine sulfoximine, an inhibitor of glutathione biosynthesis, and partially blocked by N-acetylcysteine, an antioxidant. Thus, it is conceivable that elevation of intracellular oxidant stress is a cause of the apoptosis induced by cytotoxic 2-oxoaldehyde compounds.

[Second phase 99mTc-HMDP accumulation using three phase bone scintigraphy in a case of primary breast cancer]

Accumulation of 99mTc-HMDP was recognized by three-phase bone scintigraphy in a case of primary breast cancer. A 67-year-old female was found to have a 14 x 13 mm mass in the upper lateral area of the left breast. At operation the histopathological finding was a proven solid-tubular carcinoma. On the first phase images, there was no abnormal accumulation in the tumor. On the second phase images, there was abnormal accumulation in the tumor, however, abnormal accumulation was observed followed by a decrease in accumulation. The third phase image showed no abnormal extra-skeletal accumulation. Color Doppler ultrasound sonography showed an abundance of color signals within the breast tumor. Increased 99mTc-HMDP accumulation in the second phase image might reflect tumor hypervascularization. It is concluded that three-phase bone scintigraphy using 99mTc-HMDP has the ability of positive description in primary breast cancer.

Regional cerebral blood flow in patients with schizophrenia: relevance to symptom structures

Regional cerebral blood flow (rCBF) was measured with technetium-99m hexamethylpropyleneamine oxime single photon emission computed tomography in 38 neuroleptic-treated schizophrenic patients. To improve the validity of the evaluation of symptomatology, we applied findings previously derived in a principal component analysis (PCA) of the Positive and Negative Syndrome Scale. The PCA had disclosed five orthogonal independent symptom structures (i.e., negative, hostile/excited, thought disordered, delusional/hallucinatory, and depressive components), and obtained factor scores for 70 schizophrenic subjects, including the present sample. Stepwise regression analysis elucidated some of the cortical regions in which relative rCBF predicted the severity of symptoms--namely, lateral and orbital prefrontal, lateral temporal, inferior parietal, and medial temporal regions. Findings suggested that symptom structures derived from PCA could prove helpful in elucidating the pathophysiology of neural mechanisms.

A one-dimensional current source-density analysis is applicable to the mouse accessory olfactory bulb

Field potentials evoked in the accessory olfactory bulb (AOB) of the mouse by a vomeronasal organ (VNO) volley were analyzed with current source-density (CSD) techniques. The potentials were recorded with an electrode oriented in the direction perpendicular to the laminae of the centre of the AOB in five tracks of equal spatial lattice for identical coordinates. There were little or no differences in the amplitude or time course of the potentials at equal depth among the five tracks. The CSD profile from a one-dimensional CSD analysis corresponded closely with that of a three-dimensional CSD analysis of a central track in the AOB. Furthermore, VNO-evoked field potentials were recorded in the AOB external plexiform layer while an electrode was being moved in the direction parallel to this layer. The potentials recorded at adjacent points were nearly identical and hence the related one-dimensional CSD calculations revealed no net currents along this layer. These results indicate that a one-dimensional CSD analysis is applicable to the mouse AOB.

[Comparative evaluation of 99mTc-MIBI (hexakis2-methoxy isobutyl isonitrile) and 201Tl-chloride in primary lung cancer]

We performed comparative study, using 99mTc-MIBI and 201Tl-chloride in patients with primary lung cancer. There were 42 patients with primary lung cancer. All patients underwent dual radionuclide imaging with 201Tl-chloride and 99mTc-MIBI. Regions of interest were placed over the tumor area (T) and contralateral normal lung area (N). A tumor to normal lung ratio (T/N ratio) and retention index were calculated by early and delayed ratios. In the SPECT images, the positive rate was 98% in both the early and delayed images for 201Tl-chloride and 95% in the early and 88% in the delayed images for 99mTc-MIBI. Both early and delayed T/N ratios of 201Tl-chloride were significantly higher than those of 99mTc-MIBI. The retention index of 201Tl-chloride was higher than that of 99mTc-MIBI. T/N ratio and retention index did not significantly correlated with reference to histological types. We conclude that 99mTc-MIBI SPECT can be helpful in localizing primary lung cancers. However, in our study the tumor accumulation of 99mTc-MIBI was significantly lower compared with 201Tl-chloride.